Chasing the lands

[lrgoodger]

When moving the bullet forward to maintain your distance from the lands due to erosion, is it necessary to re-tune the load due to increased case volume from moving the bullet out?

Or is it better to keep the C.O.A.L. the same and let the bullet come out of the lands as erosion progresses?

 

[40X Guy]

This is my exact question, any comments on this subject? Figured I'd resurrect this thread instead of starting a new one. This concerns a 1000 yard rifle (6 Dasher) with 800 rounds on it. I have kept same .010 off the lands with Hybrids since day one effectively chasing the lands. What are you guys doing with higher round count match rifles for LR? Keep original COAL the same or chase the lands? And what about powder charges?

I checked my COAL on day 1 with the Hybrids and it miked at 2.420, now it is 2.425 to 2.428. Initial OAL with Hornady tool with Hybrid to the lands was 1.687, now it is 1.699, but i attribute some of that difference to different bearing surface lots that I shoot.


Frank

 

[Alex Wheeler]

I have a barrel that I have never chased the lands, it keeps shooting, maybe even better than before. I have another that started giving me horizontal, so I chased the lands and it tightened right up. I measure the lands every match and keep it where it needs to be. I tweak my powder charges constantly due to temp. anyhow but I dont think moving the bullet a few thou will change pressure enough that will have to re tune. Let the groups tell you if you need to chase.

 

[40X Guy]

Thanks Zfast! It seems like this particular rifle has opened up a tad at LR and i am going to go back to my original calculations as far as seating depth. Bullet may be about .015 off the lands as per original measurements but thats what I will try. Then shoot 5 at .010 off of present throat measurement to compare..

Frank

 

[artbosco]

When moving the bullet forward to maintain your distance from the lands due to erosion, is it necessary to re-tune the load due to increased case volume from moving the bullet out?

Or is it better to keep the C.O.A.L. the same and let the bullet come out of the lands as erosion progresses?

Ask your questions here: http://benchrest.com/forum.php

I know folks who reside there that chase the lands every so often, 300 to 400 rounds. Jackie Schmidt was one of them.

On second thought, here is info that might/will cut your research time: http://benchrest.com/archive/index.php/t-71924.html

Essentially, what Jackie does is create a new barrel with fresh lands by moving EVERYTHING forward by .025", as I read it. Jackie's got the advantage of being a Master Machinist. He refreshes the barrel not the load or C.O.A.L.

 

[jsthntn247]

I noticed the same thing after the last match. My throat had moved .012 on me. Shot 5 shot groups at 300 at the old depth and the new one. The old depth had horizontal and the new depth shot 3/4".

 

[40X Guy]

Outdoorsman, thanks for the links! After reading and researching, I will shoot 5-6 of each seating depth. Original and current measurements and then go from there...

Frank